WebSphere MQ Workflow

 

WebSphere MQ Workflow on z/OS is a tool that helps companies improve their business processes. z/OS workload manager (WLM) addresses the need for:

WebSphere MQ support for z/OS workload manager uses a WLM-managed queue. It is recognized by a value of the INDXTYPE attribute called MSGTOKEN. The initiation queue associated with a WLM-managed queue must have TRIGTYPE defined as NONE, and no ordinary local queues must be associated with this initiation queue.

If a WebSphere MQ Workflow server application has the initiation queue open for input, WebSphere MQ updates a WLM worklist as part of commit processing of MQPUTs to the WLM-managed queue. The setting of TRIGGER or NOTRIGGER on the WLM-managed queue has no effect on the updating of this WLM worklist.

The PROCESS definition is used to provide the name of the application_environment associated with a WLM-managed queue. This is passed in the APPLICID attribute. Ensure that a WLM-managed queue uniquely references an associated process and that two processes do not specify the same APPLICID value.

Messages are retrieved from a WLM-managed queue using a unique message_token, which must be passed to MQGET. To do this, you use the message_token value (MQGMO_MSGTOKEN) and the get message match option (MQMO_MATCH_MSG_TOKEN). Workflow does not usually issue MQGET calls until the message is placed successfully on the queue. If the application needs to wait for the arrival of a message, it must set the match option to MQMO_NONE.

There are MQRC values for MQGET (MQRC_MSG_TOKEN_ERROR) and MQPUT (MQRC_MISSING_WIH and MQRC_WIH_ERROR). MQRC_MISSING_WIH is returned if a message, MQPUT to a WLM-managed queue, does not include the work information header (MQWIH). MQRC_WIH_ERROR is returned if the message data does not conform to an MQWIH. MQGET does not remove this header from the message.

You might experience excessive CPU usage if your z/OS system is at V2.5 or earlier and the number of messages on WLM-managed queues exceeds 500.

For further information see IBM WebSphere MQ Workflow: Concepts and Architecture, GH12-6285 and IBM WebSphere MQ Workflow for z/OS: Customization and Administration, SC33-7030.

 

Parent topic:

Using and writing applications on WebSphere MQ for z/OS


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